Sam68 regulates a set of alternatively spliced exons during neurogenesis.
Sam68 (Src-associated in mitosis, 68 kDa) is a KH domain RNA binding protein implicated in a variety of cellular processes, including alternative pre-mRNA splicing, but its functions are not well understood. Using RNA interference knockdown of Sam68 expression and splicing-sensitive microarrays, we identified a set of alternative exons whose splicing depends on Sam68. Detailed analysis of one newly identified target exon in epsilon sarcoglycan (Sgce) showed that both RNA elements distributed across the adjacent introns and the RNA binding activity of Sam68 are necessary to repress the Sgce exon. Sam68 protein is upregulated upon neuronal differentiation of P19 cells, and many Sam68 RNA targets change in expression and splicing during this process. When Sam68 is knocked down by short hairpin RNAs, many Sam68-dependent splicing changes do not occur and P19 cells fail to differentiate. We also found that the differentiation of primary neuronal progenitor cells from embryonic mouse neocortex is suppressed by Sam68 depletion and promoted by Sam68 overexpression. Thus, Sam68 controls neurogenesis through its effects on a specific set of RNA targets.
Chawla
Geetanjali
G
Howard Hughes Medical Institute, University of California, Los Angeles, 6-762 MacDonald Research Laboratories, 675 Charles E. Young Drive South, Los Angeles, California 90095-1662, USA.
Lin
Chia-Ho
CH
Han
Areum
A
Shiue
Lily
L
Ares
Manuel
M
Black
Douglas L
DL
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D005091:Exons / Q000235:genetics*; D017930:Genes, Reporter; D006801:Humans; D007438:Introns / Q000235:genetics; D051379:Mice; D055495:Neurogenesis / Q000235:genetics*; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D011485:Protein Binding; D012313:RNA / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D049031:Sarcoglycans / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; C513253:Khdrbs1 protein, mouse; D016601:RNA-Binding Proteins; D049031:Sarcoglycans; D012313:RNA